Sealing unit for downhole equipment

Abstract

FIELD: oil field equipment.SUBSTANCE: devices with a movable or fixed plunger-cylinder type connection. A sealing unit for downhole equipment, comprising a housing on which elastic seals are placed and secured with fasteners, including sealing and fastening parts. The seals are placed in transverse grooves of the housing, made with a two-level depth along the diameter with an acute-angled step between the levels, one of the ends of the grooves is made perpendicular to the axis of the housing, and the other with a recess corresponding in shape to the fastening part of the seal, the fastener is made in the form of half rings, in which one end is made perpendicular to the axis of the housing, the other – enclosing the fastening part of the seal with an outer part and entering under the acute-angled step of the groove with an inner part, and between the straight ends of the grooves and the fastener a split ring is installed.EFFECT: simplifying assembly and increasing the reliability of sealing of the sealing unit.1 cl, 2 dwg

Description

[0001] The invention relates to the field of oil and gas production industry, namely to oil field equipment, specifically to devices in which there is a movable or fixed connection of the plunger-cylinder type.

[0002] A sealing unit is known, consisting of a set of chevron seals assembled on a single housing, one after another [catalog "Baker Oil Tools" 1993. Baker Hughes Incorporated. All rights reserved. BPP / 3 / 10M / Rev. 3 / 93. p. 29].

[0003] The disadvantage of the sealing unit is low reliability during operation.

[0004] This is due to the fact that the entire set of chevron seals rests against the latter. Therefore, when the sealing unit enters the bore (cylinder), all the chevron seals may shift toward the latter, expand under compression, and fail to fit into the sealed bore. If forced, they may be damaged or ejected.

[0005] Also known for its technical essence and the result achieved is a sealing unit containing a housing, elastic cuffs and metal bushings between them [same source p. 40].

[0006] Its disadvantage is that it does not allow the seals to exit the sealing hole during operation, since under the action of pressure, the cuffs and metal bushings can move towards the latter, compressing them, and at the same time, gaps can appear between the front cuffs and bushings, which leads to the cuffs flying out.

[0007] The closest in technical essence and achieved result to the proposed one is a sealing unit containing a housing on which elastic seals are placed and secured with fasteners in the form of threaded bushings (RF Patent No. 2160859, IPC F16J 15 / 16, published on 20.12.2000, Bulletin No. 35).

[0008] Its disadvantages include the complexity of assembly due to the need to screw the bushings through the entire length of the housing and the unreliability of sealing due to the fact that threaded bushings do not ensure the centering of the sealing unit in the bushing of the downhole equipment and require large radial clearances, which reduce the reliability of the sealing.

[0009] The technical objectives of the invention are to simplify assembly and increase the reliability of sealing of the sealing unit.

[0010] The technical objectives are achieved by a sealing unit for downhole equipment, containing a housing on which elastic seals are placed and secured with fasteners, including sealing and fastening parts.

[0011] What is new is that the seals are placed in transverse grooves of the housing, made with a two-level depth along the diameter with an acute-angled step between the levels, one of the ends of the grooves is made perpendicular to the axis of the housing, and the other with a recess corresponding to the shape of the fastening part of the seal, the fastener is made in the form of half rings, in which one end is made perpendicular to the axis of the housing, the other - covering the fastening part of the seal with the outer part and entering under the acute-angled step of the groove with the inner part, and between the straight ends of the grooves and the fastener a split ring is installed.

[0012] Fig. 1 shows a general view of the device with different known forms of elastic seals.

[0013] Fig. 2 shows a cross-section of the device for one of the types of seals.

[0014] The device (Fig. 1 and Fig. 2) contains a body 1 with transverse grooves 2 made in two levels, outer 3 and inner 4, with an acute-angled step 5 between them.

[0015] Seals 6 of different shapes have a fastening 7 and sealing 8 part and are located on the outer level 3 of the groove 2. One of the ends 9 of the groove 2 is made perpendicular to the axis of the device, and the other 10 is made according to the shape of the fastening part 7 of the seal 6. The fastener is made of two half rings 11 and 12, having an internal shape in the form of a spout 13, corresponding to the space under the acute-angled step 5, and an external 14 - covering the fastening part 7 of the seal 6. The end 15 of the half rings 11 and 12 opposite the seal 6 is made perpendicular to the axis of the device. The fastening half rings 11 and 12 are fixed with the help of a split ring 16 installed between the straight ends 9 of the seal and 15 of the half rings 11 and 12. The outer surface 17 of the housing 1 is made to match in size with the bushing with which (not shown in the drawing) the sealing device interacts.

[0016] The device is assembled as follows. In a stretched state, elastic seal 6 is placed on body 1 up to groove 2 and installed on outer level 3, pushing it until it stops against end face 10 of groove 2 of fastening part 7 of seal 6. Then, half rings 11 and 12 of fastening are placed on inner level 4 and, having moved their inner part 13 under acute-angled step 5, they are fixed by inserting elastic split ring 16 between straight ends 9 of grooves 2 and 15 of half rings 11 and 12, ensuring retention of spout 13 under acute-angled step 5. That is, a dovetail connection is obtained. Since split ring 16 requires high elastic deformation, it can be made of polymer material, for example, polyethylene. In principle, all other parts of the sealing unit can be made of composite materials.

[0017] The device operates as follows.

[0018] After assembly, the device is lowered into the well as part of a stinger or plunger, where it enters a sleeve installed on downhole equipment, for example, a packer, and provides a hermetic connection with a sealing part 8, which can be self-sealing or T-shaped, triangular or of any other type. In this case, the device is centered in the sleeve along the cylindrical outer surface 17 of the body 1. The fastening part 7 of the seal 6 ensures its fixation on the body 1, when, during operation of the equipment, the seal 2 comes out of the mating sleeve on the equipment or when lowering it into the well, while on one side the fastening part 7 is held by the shape of the recess of the end 10, and on the other - by the outer 14 part of the half rings 11 and 12 of the fastener, which, in turn, are held by the step 5 by the nose 13.

[0019] Thus, a simple, easy-to-assemble and reliable sealing sealing unit for downhole equipment is developed.

Claims

A sealing unit for downhole equipment comprising a housing on which elastic seals are placed and secured with fasteners, including a sealing and fastening parts, characterized in that the seals are placed in transverse grooves of the housing made of a two-level depth along the diameter with an acute-angled step between the levels, one of the ends of the grooves is made perpendicular to the axis of the housing, and the other with a recess corresponding in shape to the fastening part of the seal, the fastener is made in the form of half rings, one end of which is made perpendicular to the axis of the housing, the other - enclosing the fastening part of the seal with an outer part and entering under the acute-angled step of the groove with an inner part, and between the straight ends of the grooves and the fastener a split ring is installed.

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